Transovarial transmission rates of Orientia tsutsugamushi in naturally infected Leptotrombidium colonies by immunofluorescent microscopy

Abstract

Transovarial transmission rates of Orientia tsutsugamushi were analyzed in naturally infected colonies of Leptotrombidium chigger mite species by improved immunofluorescent microscopy. All 377 embryos derived from 13 infected females of L. fletcheri harbored O. tsutsugamushi. Transovarial transmission rates among L. arenicola females varied between 40 and 100% with the overall transmission rate being 92.6%. However, the transmission rate in L. pallidum markedly declined over 17 generations and infected females produced fewer eggs. These observations suggested that the interaction between Leptotrombidium and O. tsutsugamushi is variable.